Exercise microdosing for skeletal muscle health applications to spaceflight.
A. Voss, Toby L. Chambers, Kevin J. Gries, B. Jemioło, U. Raue, K. Minchev, Gwénaëlle Begue, Gary A. Lee, T. Trappe, S. Trappe
Journal of Applied Physiology January 11, 2024 DOI: 10.1152/japplphysiol.00491.2023 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Experimental physiology study (within-subject exercise testing during bedrest) Peer reviewed |
|---|---|
| Sample size | 8 |
| Population | Males, mean age 29±2 years, participating in a 70-day bedrest investigation |
| Duration | Testing during a 70-day bedrest investigation; muscle biopsies obtained pre and 4h postexercise |
| Measures | Blood catecholamines (norepinephrine, epinephrine), lactate, muscle homogenate and muscle fiber-type specific mRNA levels (myostatin, IκBα, myogenin, MuRF-1, ABRA, RRAD, Fn14, PDK4, MHC I, IIa, IIx) |
| Topics | Microdosing |
| Key findings | Both the muscle power and VO2max tests increased catecholamines and lactate and altered muscle mRNA levels of exercise markers, with the VO2max test producing larger responses. Both tests affected MHC IIa fibers more than MHC I fibers in the number and magnitude of gene responses, and influenced MHC mRNA expression in a fiber-type-specific manner. |
Abstract
Findings from a recent 70 day bedrest investigation suggested intermittent exercise testing in the control group may have served as a partial countermeasure for skeletal muscle size, function, and fiber-type shifts. The purpose of the current study was to investigate the metabolic and skeletal muscle molecular responses to the testing protocols. Eight males (29±2y) completed muscle power (6x4 sec; peak muscle power: 1369±86W) and VO2max (13±1min; 3.2±0.2L/min) tests on specially designed supine cycle ergometers during two separate trials. Blood catecholamines and lactate were measured pre, immediately post, and 4h postexercise. Muscle homogenate and muscle fiber-type specific (myosin heavy chain (MHC) I and MHC IIa) mRNA levels of exercise markers (myostatin, IκBα, myogenin, MuRF-1, ABRA, RRAD, Fn14, PDK4) and MHC I, IIa, and IIx were measured from vastus lateralis muscle biopsies obtained pre and 4h postexercise. The muscle power test altered (p≤0.05) norepinephrine (+124%), epinephrine (+145%), lactate (+300%), and muscle homogenate mRNA (IκBα, myogenin, MuRF-1, RRAD, Fn14). The VO2max test altered (p≤0.05) norepinephrine (+1394%), epinephrine (+1412%), lactate (+736%), and muscle homogenate mRNA (myostatin, IκBα, myogenin, MuRF-1, ABRA, RRAD, Fn14, PDK4). In general, both tests influenced MHC IIa muscle fibers more than MHC I with respect to the number of genes that responded and the magnitude of response. Both tests also influenced MHC mRNA expression in a muscle fiber-type specific manner. These findings provide unique insights into the adaptive response of skeletal muscle to small doses of exercise and could help shape exercise countermeasures for astronauts and Earth-based populations (e.g., aging individuals).
Comparable studies
Other experimental studies on microdosing, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Microdosing Clinical Study: Pharmacokinetic, Pharmacogenomic (SLCO2B1), and Interaction (Grapefruit Juice) Profiles of Celiprolol Following the Oral Microdose and Therapeutic Dose Healthy volunteers matched for SLCO2B1 genotype | 2011 | Pharmacokinetic study | n = 30 |
| Microdosing psychedelics has no impact on cognitive function in naturalistic settings Participants during their microdosing regimen | 2023 | Observational within-subjects design | n = 17 |
| PK and PK / PD Modeling of Bcl2 Inhibitor S65487 in Patients With AML and Investigation of Nonlinearity With Microdosing Phase I/II cancer patients and healthy volunteers | 2026 | Pharmacokinetic/pharmacodynamic modeling study | |
| Technical pen-based printhead for high-precision microdosing of personalized therapies. | 2026 | Experimental study | |
| Analysis of Serotonin in Caenorhabditis Elegans Subjected to Micro-Dosing with Psilocybin| Iris Publishers Caenorhabditis elegans | 2025 | Experimental study |